This invention relates to the art of positioning tooling with respect to a workpiece, and more particularly to a new and improved method and apparatus for positioning tooling with respect to a curvilinear workpiece.
One area of use of the present invention is positioning tooling in the form of drilling and riveting tools with respect to a curvilinear workpiece in the form of an aircraft fuselage section, although the principles of the present invention can be variously applied. Of particular interest in that area of use of the present invention are the skin lap splices and butt splices which are attached during a major join of an aircraft fuselage. These areas are inaccessible to conventional C-frame automatic fastening machines, and for a long time fasteners were installed by manual methods.
Recently, there has been proposed a combination of inner and outer positioning systems which carry or support inner and outer tooling, respectively, which engage the workpiece from opposite sides thereof during tooling operations thereon. Each of the inner and outer positioning systems moves the respective tooling through a large number of axes, and movements of the inner and outer positioning systems are controlled and coordinated by a control system.
In the foregoing combination, the outer positioning means includes an outer head which typically includes a linear array of tool stations which are successively translated to the workpiece along a linear path. As the number of tools increases, the required path length for tool translation can exceed allowable limits when other positioning requirements are considered. In addition, such heads with a linear array of tool stations are limited in the degree of angular travel about an axis parallel to the fuselage longitudinal axis thereby limiting access to certain locations on the fuselage.
It would, therefore, be highly desirable to provide a new and improved method and apparatus for positioning tooling with respect to a curvilinear workpiece such as an airplane fuselage wherein a relatively large number of tool stations can be provided in a manner compatible with other positioning requirements.